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authorTejun Heo <tj@kernel.org>2011-06-01 08:27:41 +0200
committerJens Axboe <jaxboe@fusionio.com>2011-06-01 08:28:47 +0200
commit4c49ff3fe128ca68dabd07537415c419ad7f82f9 (patch)
tree58898648d2b9d896804fa98fce9eecb2724e2a75
parent4495a7d41dbda03841c2a1c2a5ce7135a45131ba (diff)
downloadlinux-stericsson-4c49ff3fe128ca68dabd07537415c419ad7f82f9.tar.gz
block: blkdev_get() should access ->bd_disk only after success
d4dc210f69 (block: don't block events on excl write for non-optical devices) added dereferencing of bdev->bd_disk to test GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE; however, bdev->bd_disk can be %NULL if open failed which can lead to an oops. Test the flag after testing open was successful, not before. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: David Miller <davem@davemloft.net> Tested-by: David Miller <davem@davemloft.net> Cc: stable@kernel.org Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
-rw-r--r--fs/block_dev.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/fs/block_dev.c b/fs/block_dev.c
index 1f2b19978333..1a2421f908f0 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -1272,8 +1272,8 @@ int blkdev_get(struct block_device *bdev, fmode_t mode, void *holder)
* individual writeable reference is too fragile given the
* way @mode is used in blkdev_get/put().
*/
- if ((disk->flags & GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE) &&
- !res && (mode & FMODE_WRITE) && !bdev->bd_write_holder) {
+ if (!res && (mode & FMODE_WRITE) && !bdev->bd_write_holder &&
+ (disk->flags & GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE)) {
bdev->bd_write_holder = true;
disk_block_events(disk);
}